Restructure the testing documentation.

I've tried to make the distinction between the DejaGNU tests and the test-suite
more clear, added a small section about generating output from the test-suite,
removed some duplication and fixed some wordings. Most of the changes are text
movements, however.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51480 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed